UK Coal, the UK's biggest coal producer, has posted losses of £62.2m for 2005.
More mines are yet to close
Year-end losses for 2005 were more than double those seen in 2004 - although the fourth quarter of last year had produced a profit.
The news demonstrates that times are still tough in the once-booming industry, amid further pit closures.
A colliery at Ellington in Northumbria is the latest to shut down with another in Yorkshire also due for closure.
Another Yorkshire mine near Doncaster is to lose 230 employees, or half its workforce.
The company retains deep mines at Daw Mill near Coventry, Kellingley and Maltby in Yorkshire and Thoresby and Welbeck in Nottinghamshire.
UK Coal chairman David Jones said that concerns about energy security meant UK-mined coal stood to do well in the government's current energy review, which is due to be completed this summer.
UK Coal, which owns the former assets of British Coal, provides about 7% of the country's energy needs.
Market prices for coal have been rising, meaning that as new contracts are signed UK Coal's income has also risen, from from £1.18 a gigajoule in 2004 to £1.35 in 2005.
In the long term, plans to lengthen mines' working lives by introducing sulphur-reducing equipment could help secure the industry's future.
Still, the UK's coal-mining industry remains tiny in comparison to its former incarnation before the miners' strike in 1984, when 180,000 miners were at work in 170 pits.